Means and method of bringing oil wells into production



1&6-250 SP FIPROU OR 2.932%001 Seam 1943- D. H. FURSE ET AL 2,328,001

MEANS AND METHOD OF BRINGING OIL WELLS INTO PRODUCTION Filed March 11, 1940 2 Shets -Sheet l DEAN H. FURS'E MOMRD i NET/MAN sk -m nk, hvvw 1943- D. H. FURSE ET AL 2,328,001

MEANS AND METHOD OF BRINGING OIL WELLS INTO PRODUCTION Filed March 11, 1940 2 Sheets-Sheet 2 I I I m -m 76d -7 so 8 J- u Mi L ,I::::7\ lq J1 A m 1 73 as 57 I F 7 Q 20 52 W k 38 /0 LL a 38 40 X 55 4 a7 30 3/ N H. FURSE LEONA/7g 4N dwa 7. M

Attorneys.

MEANS AND METHOD OF BRINGING 01L WELLS INTO PRODUCTKON Dean H. Furse, Arlington, and Leonard J. Neuman, Houston, Tex.

Application March 11, 1940, Serial No. 323,420

7 Claims.

This invention relates to means and method for bringing wells into production and in particular wells wherein the well fluids are produced from high pressure formations.

In bringing petroleum wells into production it has been proposed to locate the potential production horizons and thereafter to set casing within the well bore and to perforate such casing at the horizon or horizons from which production is to be effected. The casing is kept full of heavy mud while perforating so that a blowout should not occur during the interval necessary for removing the perforating tool and running a production string into the well. When the well controlling equipment or Christmas tree is in place washing is begun and after a material length of time the fluids from the selected horizon reach the surface and flow from the well together with the remnants of the heavy mud which gradually decrease in concentration,

Various disadvantages are inherent in this technique and it is the primary object of this invention to overcome these difficulties. As already indicated initial production includes the long column of mud from within the well casing and such mud, which is not readily separable from the desired well fluids, continues to flow from the well for a considerable period of time.

Another disadvantage with this prior art technique resides in the deleterious effect of the static head of the heavy column of mud upon the producing formation when the perforations are made thru the casing and into the formation and also the additional pressure head exerted upon the formation by the pump pressure necessary to initiate cleaning of the well, Such mud under its greater differential pressure enters the perforations and the adjacent formation and acts as a sealing material which continuously prevents the efficient movement of fluids from within the formation to the interior of the casing and hence to the flow tubing from which the well is produced.

Recognition must also be made of the fact that in order to provide reasonable assurance 45 of the elimination of the hazard of a blowout, the mud must be relatively concentrated or heavy and hence constitutes a considerable item of expense and yet at the same time does not insure against blowout when the perforations 50 are made.

A further object of the present invention is to completely enclose a well preliminary to perforating the casing so that controllable bringing the well into production may proceed from the 55 instant of perforating.

Another object is to avoid all possibility of blowout when bringing the well into production.

Still another object is to control the well completion operations in such a manner that efficient and complete production of the fluids from the producing formation may thereafter be effected.

Still another object is to provide a column of fresh water or other desirable liquid within the casing when well fluids are admitted thereto, such water being readily separable from the well fluids as cleaning progresses.

Another object is to lower a perforating mechanism on a tubing or flow string and to allow such mechanism to remain in the well after the perforating operation has been performed.

Another object is to initiate operation of the perforating mechanism from the mouth of the well.

A further and more specific object is to pro,- vicle a perforator attached to a flow string and operable by a go-devil which is dropped within the well. 7

Another object is to provide complete closure of a well preliminary to the actuation of the perforating mechanism.

It is also an object to provide a permanent record of the perforating events and/or a record indicative of the ingress of well fluids into the casing after the perforations are formed.

A still further object is to detect and selectively record vibrations initiated by the perforating operation.

Another object is to provide a record which is indicative of the effectiveness of each of the plurality of shots which are fired in succession to provide the desired passageways leading from the interior of the casing to the producing formation.

The foregoing objects together with others will be more fully apparent from the following description taken in connection with the accompanying drawings in which:

Fig. 1 is a part sectional and part diagrammatic view taken thru a well showing illustrative equipment for accomplishing the objects of the invention;

Fig. 2 is an enlarged sectional view showing the upper end of the perforating mechanism;

Figs. 3 and 4 partial sectional views showing the alternative modes of operating the perforating mechanism;

Fig. 5 shows a graphical record produced in accordance with the invention.

In Fig. 1 of the drawings the well bore I extending downwardly from the earths surface 2 is provided with a surface casing 3 which is of limited length and is cemented in place Within the well bore in a manner and for the purposes well known in the art. The upper end of the surface casing 3 is provided with a casing head 5 of conventional design, such casing head having outlets 6 and I which are provided with suitable valves or other mechanisms not shown. It is to be understood that during drilling operations the well bore I is maintained full of heavy drilling mud to prevent a blowout from pressure existing in any of the penetrated formations.

The location of a formation from which production is to be effected is determined by coring or any well known logging method. The casing string I0 is then lowered thru the surface casing 3 and extends thru the formations to be produced, such as the formation ll shown in Fig. 1. The drilling mud within the casing is then driven therefrom by a cementing operation in which a slug or slugs of cementitious material is forced downwardly within the casing and is followed by a body of fresh Water. In this manner the drilling mud is forced from within the casing and moves upwardly within the bore hole I exteriorly of the casing and may be exhausted from either or both of the outlets 6 or I in the casing head 5.

The cementitious material may be driven entirely from within the casing II! or a portion thereof may be allowed to remain as a plug but in any event sufficient cement is used to sealably secure the casing in place within the bore hole. It is to be understood that the cement and water are pumped into the casing under pressure and that, as is well known, static conditions are established when the cement has been pumped to the desired location. Such static condition is maintained until the cement has set, whereupon the casing I is completely enclosed so that no fluids can enter the casing from surrounding formations.

The next step of preparing the well for production is the lowering of the tubing or flow string into the water filled casing Hi. This tubing string includes a perforating mechanism generally referred to as 40. The tubing string and perforator assembly is lowered until the latter is opposite the formation or formations II to be produced.

Attention is directed to the fact that the tubing string 26 is provided with perforations 2| at a level which is in desired spaced relation with the perforator 43. It is understood that these perforations will be sufficient in number and location that well fluids may readily enter the tubing 26 at a point sufficiently spaced fro-m the producing formation that efficient production from the well will be effected.

When the tubing string-perforator assembly is lowered the desired distance a supporting connection and seal are provided between the tubing string 26 and the casing head 5. A Christmas tree generally referred to as is then attached to the upper end of the tubing and casing strings, it being understood that this element of the construction will be of any desired conventional design and will include such valves, chokes, gauges, etc. as may be deemed necessary for properly controlling the well during cleaning and subsequent production thereof.

In the preferred embodiment it is intended that the operati n of the perforator may be initiated by means of a go-devil to be dropped within the tubing 20. Attention is directed, however, to the fact that the invention is not confined to this specific construction as resort may be had to other operating expedients as will more fully appear hereinafter.

When using a go-devil an upward extension 26 is provided above th T-connection 21 and such extension is closed by means of a bull plug 28 which is fixed in place after the go-devil is dropped and during it descent to the perforator 40 which is constructed and operable in a manner now to be described.

In Fig. 2 the barrel M of the perforator 40 is shown as attached to the lower end of the tubing string 26 by means of an inverted cone shaped connector member 30. This cone shaped member terminate at its lower end in a head 3| having a central opening 32 thru which a movable pin 33 extends. The outer periphery of the head 3| fits closely within the barrel 4| and overlies a deformable sealing rin 34 of rubber or other suitable material. A retaining disc 35, the ring 34 and the head 3! are provided with mating opening: to receive bolts 36 which are tightened so that the material of the ring 34 is caused to flow into sealing engagement with the inner walls of the barrel 4!, the bolts 36 and the pin 33. It is to be noted that the engagement with the pin 33 is a resilient engagement and therefore permits slight movement of the pin upon impact with the head 31 of the go-devil 38 which is of any desired length that the mass thereof will be capable of effecting the desired movement of the pin 33.

An arm 45 has its upper end in close juxtaposition to the lower end of the pin 33, the opposite end of the arm terminating within a timing mechanism 46 of any suitable construction and including a shaft 41 which extend downwardly therefrom and carries an arm 48 having a contact 49. This contact moves thru an arc upon rotation of the shaft 41 by the timing mechanism 46 and sequentially encounters a series of contacts 50 which are respectively connected to the gun elements (not shown) mounted in the perforator barrel therebelow. A battery 5| is grounded to the barrel 4] at 52, th opposite terminal of the battery being connected to the contact arm 48 so that current will be successively conducted to the respective gun elements so that the perforations will be effected in a sequential and arbitrary;-

fashion.

Fig. 3 illustrates a manner of initiating operation of the perforator thru the instrumentality of a magnet 55 embedded in the lower end of the go-devil 38. When this construction is used the operation of the timing mechanism 46 is initiated thru the operation of a magnetic or electromagnetic relay 56 mounted upon a magnetizable plate 5'! extending transversely of the barrel 4!]. In this embodiment of the mechanism the cone shaped member 30 is made of a non-magnetic material so that the path of flux as indicated by the broken line 58 will pass from the magnet 55, through the go-devil 38 and thence thru a magnetizable ring 59 secured to the flow string 26 at the upper end of the barrel 46. The magnetic flux thence passes downwardly in the walls of the barrel 4!] and thru the plate 51, the relay 56 and the pin 33 to the opposite pole of the magnet 55.

The relay 56, as above indicated, is of any suitable type and may act in response to th change in magnetic flux therethru. Alternately such relay may act in response to an induced current caused by the variation in magnetic flux in the circuit as the magnet 55 approaches the head 31 of the pin 33.

The relay 56 may obviously be actuated by any suitable source of magnetic flux. For example, a strong magnetic influence may be established from a suitable source such as a solenoid 29 placed about the casing or the tubing and energized from any suitable source of electric current. Mechanical impulses imparted to the tubin may also be utilized by making the relay 56 responsive to this form of energy. The use of a magnetic flux or mechanical vibrations in the manner just set forth are particularly advantageous when it may be desired to produce a predetermined number of perforations at a given time and to thereafter, depending upon operating conditions, effect additional perforations. This may be brought about by so constructing the relay 56 and the timer 46 that actuation thereof takes place only during the interval of application of energy to the relay. Or if desired, the perforator may be constructed in sections, each of which may be responsive to any desired source of actuating energy.

It is to be noted that the perforator is shown as foreshortened at 39a and 39b (Fig. l) to illustrate the construction functioning in the manner just described and also making it possible to perforate any of a plurality of formations of which the spacing and extent are known. Such construction also admits initial production through a limited number of perforations, the operating or producing characteristics of the well thus dictating the number and location of perforations to be subsequently produced in order to obtain desired production. Likewise the constructions enable exhaustive production of one producing horizon followed by a second perforating operation and production from another horizon.

In the embodiment shown in Fig. 4 the pin 33 is a heat conductin or light transparent material and hence conducts radiant energy from the source within the go-devil 38 to the photoelectric or thermoresponsive rela 6! which initiates operation of the timer 46 to set off the perforating charges in the manner already described. This construction may be operable from either heat or light rays from the source 60 and if the latter it i preferable that the radiant energy be predominately red rays since such wave lengths in or adjacent the visible spectrum are more penetrating to mud or other materials in the water within the casing tending to prevent passage of the radiant energy between the window 6| and the pin 33. It is to be understood that the photo-electric relay 6 I may, as iswell known, be responsive to either the heat or light rays from the source 60 which may therefore take on any of numerous form of element adapted to provide radiant energy and which is energized from a source encased within the go-devil 38.

Each of the perforating charges, which are sequentially set off b means of the mechanism and in the manner above described, creates a violent disturbance, one portion of which arises at the instant of detonation and another portion arising fro-m the impact with and penetration of the casing by the projectile. This disturbance causes vibrations to travel along the casing or tubing at a high rate of speed. The invention takes advantage of these waves by providing a transducer to pick up the vibrations which are transmitted upwardly from the source of the disturbance. In gaccordance with the illustrated embodiment in i Fig. 1 the geophone is attached to the surface casing 3 but it is to be understood that the geophone may be placed at any suitable point and or geophone 65 (Fig. 1) which is so positioned as iii-eater may, if desired, be placed upon the earths surface 2 in proximity to the bore hole.

The output of the geophone 65 is conducted by wires 66 to an amplifier-filter unit 6'! which includes such band pass filters as may be deemed necessary. It may be desirable, for example, to provide a band pass filter for segregatin the band of frequencies containing the major portion of the energy of the waves set up by the perforating impulses. This amplified energ is trans.- mitted by means of conductors 68 to a recorder unit 69 whereby the impulses are recorded as a trace '10 as shown in Fig. 5.

As soon as initial perforation [2 are formed in the casing l0 and the adjacent formation, the inrush of the formation fluids under pressure likewise sets up add i ti wgl ibrat ion s which are also transmitted alpngthe p asing to the mouth of the welwlie s'e vibrations are also converted into e1ectrical iiifpulses by the geophone 65 or a second geophone (not shown) and a second band pass filter incorporated in the amplifier filter unit 67 segregates the energy of the band of frequencies encompassed by such disturbance, such energy being transmitted thru the conductors H to the recorder 69 so that a trace such as that shown at 72 in Fig. 5 is produced upon the recording tape 73 in the recorder 89. A record of such ingress of fluids gives a signal of pressure conditions before difficulties have an opportunity to develop at the mouth of the bore hole.

It is believed that the operation of the construction described is apparent from the foregoing description. By Way of summary, attention will, however, be directed to the operation of the disclosed construction and further explanation of the results obtained as revealed by the graphical records shown in Fig. 5. As previously explained the flow tubing 21! and the perforator 40 are positioned within the casing it after such casing has been set in the well bore l. The well is then closed by affixing the Christmas tree 25 to the upper end of the flow string. With. the bull plug 28 removed the go-devil 38 is placed within the extension 26 and at such instant an impulse is imparted tothe assembl as by tapping the go-' devil upon the extension 26. The recording mechanism 69 is placed in operation at such time and the impulse produced. as described is recorded as indicated by the fluctuation of the graph at 15. While the go-devil 38 travels downwardly within the flow tubing 20 any impacts thereof with the sides of the tubing will cause fluctuations in the graphical records such as those indicated at 16.

When the go-devil 38 engages the head 37 of the pin 33 an impulse as recorded at T? is set up. At this time the recorder mechanism is speeded up so that the succeeding and rapidly occurring events will be shown at greater detail upon the tape 13. When the contact carrying arm 48 engages the first contact 50 one of the perforating charges is set off and produces a fluctuation in the curve as indicated at 7B. This portion of the curve is produced by the detonation itself, whereas, the succeeding portion of the curve T9 is produced by the actual penetration of the casing by the projectile. The recurrence of this curve at indicates that similar results were obtained when the circuit was closed thru a second contact 50 by the operation of the timer 46. It is to be noted that subsequent to the fluctuation in the curve as shown at 80 the succeeding contact failed to produce the desired results, whereas, the following contact was again effective in proiiiiiiii ducing an operation as evidenced by the fluctuation 83 in the curve. The portion 82 of the curve shows that the succeeding charge was set off but that such charge was insufficient to produce the desired perforation.

From the foregoing it is believed apparent that the record of events as indicated by the trace 10 upon the recording tape 73 provides a valuable and informative permanent record which clearly indicates the effectiveness of the perforating operation. It is understood that at the same time the well has been completely closed in so that there is no danger of blowoutfrom the high pressures which ma exist in the producing formation or formations I E.

Simultaneous with the production of the record H3 a second trace i2 is formed, this trace also including indications at 85 and 85 of the instant when the go-devil 38 was placed within the tubing string and the instant when the pin 33 was engaged thereby. A more important phase of this trace is shown however at 8'1 where the record of the incoming fluids thru the perforations i2 is shown. With this information at hand it is possible to initiate and continue the Well cleaning and production operations so that the most desirable conditions will be established in the newly penetrated producing horizon. It is to be understood of course that, if desired, the band pass filters may be omitted and a single composite record produced and utilized to convey the same information as the separate records.

Broadly the invention comprehends means and method of efliciently bringing oil wells into production and at the same time avoiding the hazard of blowout as the result of perforating operation.

What is claimed is:

1. A method of bringing wells into production comprising the steps of, encasing the bore hole by an imperforate casing cemented in place and filled with water, lowering a perforator within the casing upon a how string, closing the well at it upper end, sequentially forming perforations through the casing and into the formation to be produced, and recording at the mouth of the well the vibrations created by the perforating operation.

2. A method of bringing wells into production comprising the steps of, encasing the bore hole by an imperforate casing cemented in place and filled with water, lowering a perforator within the casing upon a flow string, closing the well at its upper end, sequentially forming perforations through the casing and into the formation to be produced, and recording at different frequency levels the vibrations set up by the perforating operation and the resulting ingress of fluids through the perforations.

3. The method of bringing a well into productil tion comprising the steps of, closing the well bore by an imperforate casing set therein, p0sitioning a flow string Within the casing, closing the well at its upper end, perforating the casing, and simultaneously producing a record of the perforating operation.

a. The method of bringing a well into production comprising the steps of, setting an imperforate casing within the well bore, closing the casing at the top of the well about a flow strin extending therein, perforating the casing, and producing a graphical record of the vibration set up in the casing by the influx of formation fluids through the perforations.

5. An apparatus for controllably bringing a well into production comprising the combination of, an imperforate casing set in the well bore, a flow string extending downwardly within said casing, said flow string including perforating means for producing perforations from within the casing to the formation to be produced, means for closing in the well preliminary to perforating the casing, means for actuating said perforating means, whereby the well is controllably cleaned and produced through the flow string, and means for recording the vibrations set up by the perforating means and the subsequent ingress of fluids from the producing formation.

6. An apparatus for controllably bringing a well into production comprising the combination of, an imperforate casing set in the well bore, a flow string extending downwardly within said casing, said flow string including perforating means for producing perforations from within the casing to the formation to be produced, means for closing in the well preliminary to perforating the casing, means for actuating said perforating means, whereby the well is controllably cleaned and produced through the flow string, and means at the mouth of the well bore for separately recording the vibrations set up by the perforating means and the vibrations set up by the fluids thereafter entering through the perforations.

'7. In a device of the class described, a tubing string adapted to be lowered into a cased bore hole and having perforations for the admission of well fluids thereto, a gun perforator attached to the tubing string below said perforations, said gun including a plurality of means adapted to be energized by an electric current to perforate the casing, means operable to actuate said last mentioned means in sequence after the casing and tubing are closed at their upper ends, and means for recording the vibrations set up in the tubing string.

DEAN H. FURSE. LEONARD J. N'EUMAN. 

